What is sq.rt.(x+3) x sq.rt.(x-3) ?

the answer is 0.

sq rt (0 + 3) x sq rt (0 -3)

But incase you still need help, there’s two ways to do it. There’s the long way which would be: X x X= X^2, X x (-3)= -3X, 3 x X= 3X and 3 x -3=-9. This gives you X^2 -3X +3X -9 or just X^2-9 after the +/- 3X’s cancel each other out. Then you find the square root of it which is impossible because you cant find the square root of a negative.

Or you use a shortcut, knowing that when you have the same problem multiplied by itself, with the only difference being the + and -sign, as in (a+b)(a-b) you will only have a x a and b x b, because the rest will cancel out. As proof: X x X= X^2, 3 x -3= -9, so the answer is: X^2 -9. Again, you cant find the square root of a negative.

so in your case a = x + 3

and b = x – 3

so sqrt(x + 3) x sqrt(x – 3) = sqrt((x + 3) x (x – 3))

which = sqrt (x^2 – 9)

and sqrt (x^2 – 9) can’t be simplified any further

Therefore, your answer is

sq.rt (x^2-9)